An animal protection group has accused the Petland Inc. pet store chain of scheming to sell sick puppies bred in filthy conditions to thousands of unsuspecting people.

Puppies/Petland logo. The Humane Society sues Petland, accusing the chain of a scheme to sell sick puppies as healthy.

Petland intentionally misled thousands of customers into believing the puppies came from the finest breeders and were healthy, the Humane Society of the United States said in a lawsuit against the company, which is based in Chillicothe, Ohio.

The group said it conducted an investigation showing that many of the puppies sold by Petland in its 131 U.S. stores were bred in mills in horrific conditions or through brokers such as The Hunte Corp., based in Goodman, Mo. Investigators for the Humane Society saw "puppies living in filthy, barren cages reeking of urine, with inadequate care and socialization," the complaint said.

The lawsuit was filed Monday in U.S. District Court in Phoenix by attorneys representing members of the Humane Society, which calls itself the nation's largest animal protection organization, and other pet owners who say they were sold sick puppies.

Petland, which also has 61 stores overseas, said Tuesday it was outraged and disappointed by what it called false accusations.

"At Petland, we offer healthy, happy and well-socialized pets to our customers," Petland vice president Joe Watson said in a statement. "As our business requires that our customers be highly satisfied, it only makes sense that we would do everything possible to ensure that we provide healthy puppies."

A telephone message seeking comment from Hunte was not immediately returned.

The plaintiffs are seeking changes in how the puppies are bred and financial damages to help recover veterinary costs they say were associated with keeping their puppies alive. They also are seeking to stop what the lawsuit alleges are unfair and deceptive sales practices.